This invention relates generally to packaging and packaging containers and more particularly to packaging structures particularly suitable for packaging in sealed state tools and instruments for medical treatment such as hypodermic syringes, hypodermic needles, surgical scalpels and scissors, and catheters.
More specifically, the invention concerns packaging structures (hereinafter referred to as "container structures" or simply "containers") which can be subjected to gas sterilization treatment with gases, principally ethylene oxide, steam, and the like to simultaneously sterilize the container and also its contents and, furthermore, when used for packaging an article such as a medical instrument, can be readily unsealed for taking out the article, and which, moreover, can be thus unsealed to produce an unsealed access opening which is in a neatly opened state. The invention further relates to a readily unsealable sealed package comprising a commodity and the container containing the commodity in sealed and sterilized state and to methods of producing the container and the sealed and sterilized package.
Tools and instruments for medical treatment, most of which are intended to be disposable after a single use as a premise in modern medical practice, are packaged with paper impervious to microorganisms and then subjected to sterilization processing with a gas such as ethylene oxide gas or steam. Alternatively, these articles are packaged in containers of synthetic resin film and subjected to sterilization processing with inoizing radiation rays such as gamma rays or electron rays. Thus, the sealed articles can be maintained in a sterile state until they are to be used.
The above mentioned sterilization treatments are generally employed. While the method of sterilization with ionization radiation rays exhibits excellent sterilization efficiency, it requires complicated equipment and is expensive. For this reason, the most generally utilized method at present is that of gas sterilization. Accordingly, in order that gas sterilization, which is the most general sterilization method for packages of medical supplies, will become possible, the most desirable packaging material is a paper of having a characteristic such that it will pass gases therethrough but will not pass microorganisms therethrough. In actual practice, such a paper material is most widely used at present.
A packaging container made of such paper generally has sealing parts on which thermoplastic synthetic resin layers are formed to be mutually heat bonded together at the time of packaging and sealing to form a tight seal. When this seal is to be broken or unsealed, the most commonly used procedure is to pull apart and tear the sealed part. Not only is this procedure difficult, but the tearing occurs, not between the thermoplastic resin layers which participated in the forming of the sealed part, but at the inner parts of the paper layer where the bonding strength is weak. For this reason, paper dust called paper fluff or fuzz is scattered toward the surroundings and adheres to the medical commodity, which has been sealed up to that time. This is not only unsanitary but also gives rise to problems such as the risk of the paper dust infiltrating into the bodies of patients to be treated with the medical commodity.